A dual-fuel engine may operate with only one source of fuel and/or may operate with two separate sources of fuel. For example, a dual-fuel engine may be configured to operate in a single-fuel mode when only a liquid fuel is supplied and/or may be configured to operate in a dual-fuel mode when both liquid and gaseous fuels are supplied. When the engine operates in the dual-fuel mode, both gaseous and liquid fuels may be introduced into a combustion chamber of an engine to result in combustion therein.